Medically reviewed by Jonathan Purtell, RDN Key Takeaways Vitamin B12 supports energy, red blood cell formation, nerve function, and DNA production.A deficiency can cause fatigue, weakness, headaches, ...

Vitamin B12 is an essential nutrient that we need to maintain nervous system function and overall health. It's also a very popular dietary supplement, even though most people can get enough of it from ...

Even if you have a balanced diet, you might not be getting enough vitamin B12. The reason? B12 is found almost exclusively in animal foods. For instance, beef is a top source of B12. Just one 4-ounce ...

Q. I was recently told my vitamin B12 level is low. How can I get it back into range? A. Vitamin B12 is one of those nutrients that quietly does a lot of heavy lifting in the body. Also known as ...